Geothermal heating and cooling is based on one simple fact: that 6 feet down in the ground the temperature is the same—between 50˚F and 60˚F- the whole year round. This means that it is relatively cool in the summer, and relatively warm in the winter. Geothermal heating is thus quite different from solar heating: solar heating works worst when you most need it--in the cold, cloudy, snowy conditions of winter; the source for geothermal heating and cooling is not affected by the weather.
Inventor of The Tipping Point and author of Blink, Malcolm Gladwell recently started a blog that he contributes to occasionally. His dad recently installed a geothermal system for heating and cooling and Malcolm was impressed, and got dad (a mathematician) to explain it, (which he does well) and finishes himself with the conclusion (common at TreeHugger) :"One of the frustrating things about the current discussion over our dependence on imported oil is the persistent notion that real solutions will require some future technological breakthrough. I think we have a lot of the answers. We just haven’t made consumers and public officials aware of them." ::Malcolm GladwellGladwell's father writes: